Polarization processes in electrorheological fluids based on conductive polymers

Abstract

Electrorheological (ER) fluids are composed of dielectric particles dispersed in an inert liquid of low electric permittivity. Upon the application of an electric field ER fluids rapidly solidify, or increase their viscosity. Characteristic increase of the viscosity of ER fluids is due to the formation of particle chains that bridge the electrodes. This process is greatly affected by polarization processes within the solid phase and at the surface of the grains. These phenomena are governed by dopants, functional groups, structure of the solid particles and the solid/liquid interface. To find relations between parameters of the ER effect and material properties of components of ER fluids, two main types of the materials were investigated: conjugated polymers [polyphenylene (PPP), pyrolyzed polyacrylonitrile (PAN) and polythiophene] and solid electrolytes based on polyacrylonitrile complexed with inorganic salts. It was found that the ER activity resulted from surface polarization processes due to the presence of polar species (PAN) or bulk polarization related to mobile ions (PPP). Polythiophene, despite the presence of a conjugated system of multiple bonds, showed only residual ER effect. Solid electrolyte-based fluids exhibited relatively high activity originated from ionic polarization.

Investigation of vibration damping properties of electroactive polyanthracene/silicone oil dispersions

“…(Dong et al, 2019). The electric field induced structure forms due to the conductivity and dielectric constant differences between dispersed particles and dispersing medium for conduction and polarization models, respectively (Krzton´-Maziopa et al, 2006). For PAT/ SO dispersion system, the slope of the fitting line is 1.5 indicating that the driving force is the conduction model (Figure 9).…”

Ionic liquid-based organically modified silica for the development of new electrorheological fluids

“…The physical mechanism of ER enhanced by the presence of ILs attached on the silica particle surface may be attributed to two polarization effects, ionic and surface polarization, due to the presence of mobile ions or polar groups at the fluid-particle interface. [48]. The solid curves in Figure 9 corresponed to the fit of the experimental data by the Cole-Cole model [46]:…”